The present invention relates to a system and garment for detecting or monitoring the movement of a person, animal or an object such as a machine and in particular the movement of parts thereof. For example, the present invention can be used for monitoring or detecting the movement of the arms and legs of an athlete or patient. Similarly, the present invention may also be used for monitoring or detecting the movement of a robot or machine.
The technology that is the subject of the present invention may find use in a broad range of applications including, but by no means exhaustively, training or rehabilitating skeletal joints or muscular injuries, biomedical monitoring, medical textiles, triage service for injured soldiers and other military and security applications. According to another example, the present invention may be used as a tool in adjusting the shape or configuration of a medium such as textiles, and more specifically the shape and configuration of a sail of the yacht. According to yet another example, the present invention may be applied to musical instruments where the sound produced is a function, or controlled, by the movement of a person or object.
An example of a system that measures the movement of a human hand is described in U.S. Pat. No. 6,701,296. The system comprises a series of goniometers that detect hinge like movements or joint movement in a person's hand. Joint movement is monitored using a series of strain gauges that change in electrical conductivity as the strain gauges are stressed. Each strain gauge forms part of a glove worn by a person and the strain gauges are located on the palm or upper faces of the glove. Changes in electrical signal are received when the person curls their fingers and the electrical signals may then be interpreted to carry out specific functions using computer interfaces.
Another example is that the device described in a paper entitled “A WEARABLE CONDUCTIVE FIBER SENSORS FOR MULTI-AXIS HUMAN JOINT ANGLE MEASUREMENTS”, by Peter Gibbs and Harry Asada, Journal of NeuroEngineering and Rehabilitation 2005, 2:7. The paper describes a device in the form of a conventional knee support comprising a knitted fabric sleeve containing rayon, cotton, and rubber. An electrical conductive fibre is permanently attached to the knee support above the knee joint at one conductive point, and spans across the joint on the outside of the knee support fabric. The conductive fibre is not sewn or woven into the sleeve, as it needs to freely slide across the joint. Coupled to the opposite end of the conductive fibre is an elastic cord which is permanently attached to the sleeve at a position that is below the knee when worn and places the conductive fibre under tension during use. As the joint moves, the elastic cord changes length, pulling the conductive fibre past another conductive point that is permanently stitched into the fabric so as to form a circuit between the conductive points. As the joint is flexed, the length of the conductive fibre between the conductive point increases and electrical resistance between the two conductive points is measured using a voltage divider or bridge circuit. Ultimately, changes in resistance can be interpreted and analysed to provide information relating to joint movement.
In order to maintain reliable operation, the device is dependant on the elastic cord maintaining the conductive fibre under tension at all times. In the event of the elastic cord failing, the length of the conductive fibre between the points will not be representative of the degree of flex in the knee joint. In addition, in our view the design is not particularly suited to situations where the conductive fibre is located in the inside of the joint such as behind a knee or on the inside of an elbow.
It is an object of the present invention to provide an alternative system that can be used for monitoring the movement of a joint or deformed surface.